BALTIMORE (WJZ) - The killing of teenager Phylicia Barnes stunned the city and made worldwide headlines. Barnes disappeared from a Northwest Baltimore apartment in December of 2010. Her body was found months later. Now the trial begins for her accused killer-her sister's ex-boyfriend.

There is a gag order in this case. Attorneys or any parties involved are not allowed to speak to the media. The judge has forbidden any members of the media to be inside the courtroom during the jury selection, which is expected to last at least two days.

A lot of attention will be focused on a sex video that prosecutors say involved Barnes and her accused killer and new insight into the motive: why would anyone want to kill the young honor student from North Carolina?

Barnes was just visiting a relative in the city during her holiday break when prosecutors say the defendant strangled her and then disposed of her body.

Sixteen-year-old Phylicia Barnes disappeared more than two years ago without a trace, launching the largest search for a missing person in Baltimore history until her naked body was found floating in the Susquehanna River.

Police had long suspected Michael Johnson, the 28-year-old former boyfriend of Barnes' sister. They say he was the last person to see her alive-but as his lawyer said, that doesn't make him guilty.

"Baltimore City, they made their promise. They said, we know-we believe you're the person and we're going to get you," said Johnson's lawyer, Russell Neverdon.

Some of the prosecution's strongest evidence is a neighbor who says he saw Johnson struggling to carry a 35-gallon tub from the apartment. They believe that tub contained Barnes' body.

Prosecutors plan to play a video they say shows Barnes and Johnson, along with her sister and his brother, engaged in sexual activity. They say Barnes' accused killer texted and called her at least 500 times in the months before her disappearance and that in intercepted phone calls after her death, they say he spoke of fleeing to Brazil, where he could not be extradited to face murder charges.

"I would hope that he would tell exactly what he had in that container, tell his family the truth about what happened to Phylicia Barnes," said Harry Watson, Barnes' cousin.

Back at the apartment complex off Reisterstown Road where Barnes initially disappeared, there's hope justice will prevail.

"Definitely for the family. I think the family definitely needs to rest. They need to find out what's going on," said Veronica Delrio. "She was so young. That's really the sad thing about it."

Johnson's lawyers say they have another witness who claims to have seen Barnes alive later in Cecil County, near where her body washed up.

Police say there was no evidence that Barnes was sexually assaulted.

Barnes was visiting from North Carolina, where she lived. She planned to attend Towson University.